// Flying
this.addAbility(FlyingAbility.getInstance());
// Tribute 2</i>
this.addAbility(new TributeAbility(2));
// When Shrike Harpy enters the battlefield, if tribute wasn't paid, target opponent sacrifices a creature.
TriggeredAbility ability = new EntersBattlefieldTriggeredAbility(new SacrificeEffect(new FilterCreaturePermanent("a creature"), 1, "target opponent"), false);
ability.addTarget(new TargetOpponent());
this.addAbility(new ConditionalTriggeredAbility(ability, TributeNotPaidCondition.getInstance(),
"When {this} enters the battlefield, if its tribute wasn't paid, target opponent sacrifices a creature."));
}